﻿using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

    namespace Calculator
{
    public partial class Form1 : Form
{
        public Form1()
        {
            InitializeComponent();
        }
        Double leftnum, rightnum, result;
        String Flag;
        private void button1_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "Sin";
        }

        private void button2_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "Cos";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "Tan";
        }

        private void button4_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "lg";
        }
        //7
        private void button5_Click(object sender, EventArgs e)
        {
            textBox1.Text += "7";
        }
        //8
        private void button6_Click(object sender, EventArgs e)
        {
            textBox1.Text += "8";
        }
        //9
        private void button7_Click(object sender, EventArgs e)
        {
            textBox1.Text += "9";
        }

        private void button8_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "/";
            textBox1.Text = "";
        }

        private void button9_Click(object sender, EventArgs e)
        {
            textBox1.Text += "4";
        }

        private void button10_Click(object sender, EventArgs e)
        {
            textBox1.Text += "5";
        }

        private void button11_Click(object sender, EventArgs e)
        {
            textBox1.Text += "6";
        }

        private void button12_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "*";
            textBox1.Text = "";
        }

        private void button13_Click(object sender, EventArgs e)
        {
            textBox1.Text += "1";
        }

        private void button15_Click(object sender, EventArgs e)
        {
            textBox1.Text += "2";
        }

        private void button14_Click(object sender, EventArgs e)
        {
            textBox1.Text += "3";
        }

        private void button17_Click(object sender, EventArgs e)
        {
            textBox1.Text += "0";
        }

        private void button18_Click(object sender, EventArgs e)
        {
            textBox1.Text += ".";
        }

        private void button19_Click(object sender, EventArgs e)
        {
            rightnum = Convert.ToDouble(textBox1.Text);
            if(Flag=="+")
            {
                result = leftnum + rightnum; 
            }
            else if(Flag=="-")
            {
                result = leftnum - rightnum;
            }
            else if(Flag=="*")
            {
                result = leftnum * rightnum;
            }
            else if(Flag=="/")
            {
                result = leftnum / rightnum;
            }
            else if(Flag=="Sin")
            {
                result = Math.Sin(leftnum);
            }
            else if(Flag=="Cos")
            {
                result = Math.Cos(leftnum);
            }
            else if(Flag=="Tan")
            {
                result = Math.Tan(leftnum);
            }
            else if(Flag=="lg")
            {
                result = Math.Log10(leftnum);
            }
            textBox1.Text = result.ToString();

        }

        private void button20_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "+";
            textBox1.Text = "";
        }

        private void button21_Click(object sender, EventArgs e)
        {
            textBox1.Text = "";
        }

        private void button16_Click(object sender, EventArgs e)
        {
            leftnum = Convert.ToDouble(textBox1.Text);
            Flag = "-";
            textBox1.Text = "";
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}
